Experimental study of acoustically induced hydroxyl radicals in hydrogen peroxide systems based on fluorescence analysis

The hydroxyl radical (·OH), an extremely reactive oxidizing agent, can interact with both brittle and hard materials, such as single-crystal silicon carbide (SiC), facilitating material removal via ultrasonic-assisted chemical mechanical polishing (UCMP). It is crucial to explore the generation mechanism of acoustically induced ·OH radicals within the UCMP process. This study investigated the influence of ultrasonic duration, initial solution temperature, frequency, power, and initial hydrogen peroxide (H₂O₂) concentration on the ·OH radical yield in the H₂O₂ system based on fluorescence analysis. Furthermore, it elucidates the quantitative relationships between the parameters and ·OH radical generation. The experimental data showed that ultrasonic vibrations significantly enhanced the decomposition of H₂O₂, with the ultrasonic duration being key to ·OH radical production, increasing 32.42 times in 30 min without a water-bath. Water-bath conditions reduce the thermal effects, yielding ·OH at a rate of 0.1826. The initial temperature had little impact within a specific range, and the peaking ·OH yield increased at 0.0662 from 20 to 50 °C. Lower frequencies and higher powers enhanced the ·OH yield by 5.37 to 10.126 times. Low H₂O₂ concentrations produced high ·OH radicals, peaking at 3.753 μmol/L at 1.5 wt%. These results are vital for improving UCMP efficiency and surface quality.